Continuous cycling of carbon-based capacitive deionization systems: An evaluation of the electrode performance and stability

•Electrode pore size distribution and apparent morphology are immune to oxidation.•Electrode oxidation will increase oxygen-containing functional groups on the surface.•Slight oxidation helps to improve the desalination performance of the electrode.•The degree of oxidation of the carbon electrode corresponds to the number of cycles.•Electrode oxidation evaluation system is of great significance to CDI technology.